Measurement of regional myocardial blood flow using Positron Emission Tomography Three PET bloodflow methodologies will be investigated 0-15 labeled water bolus injection, N-13 labeled ammonia, and Rubidium 82. Methods for compensating for partial volume effects and "split over" from the LV cavity will be developed. The resultant flow values will be compared to microsphere measurements in 10 dogs. 6 dogs have been studied to date. Preliminary results presented at the 1988 Society of Nuclear Medicine meeting. A techniques for making bloodflow measurements without a carbon monoxide bloodpool scan has been developed and validated (results to be presented at the June 1989 SNM meeting).